| abstract |
Flow-through fluid heaters useful, e.g., for the preheating of exhaust gas streams prior to catalytic treatment thereof, are made by bonding an electrically conductive metallic film or foil to at least one pre-sintered flexible ceramic foil substrate to provide a flexible, electrically conductive ceramic/metallic heating element, that element then being formed into a crimped sheet or base sheet for incorporation into a honeycomb structure which includes a plurality of open channels extending from one surface of the structure to another surface of the structure, formed by one or more contacting combinations of crimped sheet and base sheet. Catalytic coatings may be applied to the preheaters to provide a heater/converter with very rapid light-off characteristics. |